RU2491135C1 - Soil slurry-ground mixture (versions) for remediation of disturbed lands and method of remediation of borrow pits and disturbed lands - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: invention relates to agriculture. The soil slurry-ground mixture for remediation of borrow pits and disturbed lands is proposed, which consists of two mixtures. At that the mixture used as a lower remediation layer comprises, volume percent: drill cuttings - 50-65, sand or sandy-loam soil - 16-25, peat - 15-23, the rest - active neutralising and ameliorating supplements, including gypsum or phosphogypsum in an amount of 2-3% of its volume. The mixture used as the upper remediation layer comprises, volume percent: drill cuttings - 35-50%, sand or sandy-loam soil - 20-30%, peat - 27-32.5%, the rest - active neutralising and ameliorating supplements, including gypsum or phosphogypsum in an amount of 1.5-2% of its volume. Also a method of remediation of borrow pits and disturbed lands is proposed.

EFFECT: group of inventions enables to improve fertility of disturbed lands and use more effectively the natural resources in Western Siberia.

10 cl, 1 tbl, 1 ex

Description

The invention relates to the field of construction, reclamation and land reclamation in oil-producing areas by restoring the topography and soil fertility with the simultaneous disposal of industrial waste - drill cuttings. The application describes a method for reclamation of disturbed lands and the composition of the compositions used for these purposes - soil sludge-soil mixtures (SSSH).

The technology for the preparation and use of SPSG for reclamation of disturbed lands involves the processing (use) of drill cuttings (consisting of drilled rock and spent drilling mud) into artificial soil-like fertile soil with subsequent use of the resulting material in the reclamation of disturbed lands of various origins: industrial ones with disturbed soil and plant cover, oil-contaminated, occupied by cluster sites, barns, sludge collectors, exploratory wells, to Origors of communications, dry pits, etc.

For the prototype for the object of both declared objects (soil mixture (options) and reclamation method), the well-known composition (RU, patent No. 2293103 C2, IPC C09K 17/00, A01B 79/02, published on 04/10/2006) was adopted as a composition for reclamation of quarries and disturbed lands, including peat sand mixture, drill cuttings (BS), as well as active neutralizing and reclamation additives, and a method for reclamation of quarries and disturbed lands, including the preparation of two mixtures, their exposure to undergo physicochemical sorption and neutralization of toxicants, protractor ovku to the place of installation and layering them in layers.

The disadvantages of the known composition are:

- the structurelessness of the clay BS introduced into the composition, the clay-colloidal phase of which swells significantly during waterlogging, loses strength, can become fluid and washed out of the composition, causing the migration of toxic waste components, environmental pollution, leading to a sharp decrease in moisture filtration, aeration, fertility of the mixture, survival and plant growth at the biological stage of reclamation;

- the use of significant quantities of peat, which is a valuable and limited natural resource, as well as high-quality building sand, which involves the development of additional quarries of peat and sand, which requires the allocation and removal of land, leading to additional negative impact on nature;

- lack of connection between the degree of salinization or contamination of drill cuttings and the amount of reclaimed material;

- an increase in the cost of the composition due to the use of scarce additives (Soylex, Degradoilas, UNI-REM, etc.), some of which are no longer available or banned (the prototype provides for the use of the sorbent “Unipolymer” - a urea-formaldehyde poroplast - toxic, emitting phenol).

The disadvantages of this method of reclamation include:

1) unsatisfactory indicators in terms of resistance to erosion, moisture retention and plant growth in the dry period when using 100% peat-sand mixture as the top reclamation layer;

2) use as a lower reclamation layer of a composition with an excessive content (49-69%) of a peat-sand mixture; at the same time, at a depth, under anaerobic conditions, the process of destruction and neutralization of oil products and other ecotoxicants does not take place effectively;

3) a significant change in soil pH as the depth changes: from a weakly acidic medium (4-5 pH units) in the upper layer to slightly alkaline in the lower layer (due to the use of quicklime), which often prevents the restoration of local plant species in reclaimed territories.

The problem to which the claimed group of inventions is aimed is to increase the efficiency of reclamation of disturbed lands with the associated disposal of drilling waste.

A single technical result obtained by the implementation of the claimed group of inventions is to increase the fertility and environmental safety of the mixture of soil sludge-ground (SPSH); more efficient use of local, characteristic for oil producing regions of Western Siberia, natural resources - soils (peat, natural sand); neutralize the effects of salts and other possible toxicants on plant biocenosis.

The indicated technical result for the SPSHG facility according to its first embodiment is achieved due to the fact that the content of components in the mixture volume is: drill cuttings - 50-65%, sand or sandy loam soil - 16-25%, peat - 15-23%, the rest - active neutralizing and reclamating, while gypsum or phosphogypsum in the amount of 2-3% of the mixture volume is used as the main reclamation additive.

This soil sludge-soil mixture (SPSH I) is used as the lower, most voluminous reclamation layer in the elimination and reclamation of sludge pits and quarries.

The specified technical result for the SPSHG facility in the second embodiment is achieved due to the fact that the content of components in the mixture volume is: drill cuttings - 35-50%, sand or sandy loam soil - 20-30%, peat - 27-32.5%, the rest - active neutralizing and reclamating, while gypsum or phosphogypsum in the amount of 1.5-2% of the mixture volume is used as the main reclamation additive. This soil sludge-soil mixture (SPSH II) is used, as a rule, as the upper, fertile layer for the biological stage of the reclamation of quarries and disturbed lands.

Improving fertility and environmental safety by neutralizing the effects of possible toxicants in the soil sludge-soil mixture is achieved by using gypsum or phosphogypsum as the main structural ameliorant, which ensures irreversible coagulation of the clay-colloidal phase of the sludge, improving the filtration and air permeability of the mixture, as well as:

a) the use of fibrous (top) peat, as well as sandy loam soil, with increased sorption ability to neutralize the effects of salts, hydrocarbons;

b) the use of a dose of active neutralizing and reclamating additives, depending on the presence and level of contamination of drill cuttings with salts and hydrocarbons.

c) obtaining a near-neutral SPSH reaction due to the mutual neutralization of its components: the initial alkaline environment of the sludge is neutralized by adding acid peat or phosphogypsum to pH 6.0-7.5, if necessary, the reaction of the soil medium is adjusted by the addition of gypsum or phosphogypsum (to lower the pH) to provide a pH of 7.0-7.5 in the lower layers (mixture type I) and 6.0-7.0 in the upper layer (mixture type II).

One of the most important differences between fertile soil and lifeless clay or other colloidal medium is the presence of a structure, i.e. soil aggregates and pores between them, which ensures the movement of moisture and air. Drill cuttings contain a significant amount of clay-colloidal phase (about 50%) and have no structure. When dried, the sludge turns into large stony lumps, and when moistened, it passes into a plastic state. The structurelessness of drill cuttings in deposits in Western Siberia is enhanced when the exchange complex of clay particles (montmorillonite, etc.) is saturated with potassium and sodium ions, which occurs when salts are introduced - KCl, NaCl and / or when saline geological formations pass through.

In this prototype, additives that cause sharp coagulation, i.e. aggregation of clay-colloidal particles into larger formations. The introduction of gypsum (CaSO ₄ ) into the LNGF composition as the main reclamation additive ensures saturation of the ion-exchange complex of clay-colloidal particles with calcium, release and leaching of excess potassium and sodium salts into the underlying soil layers, irreversible coagulation of the clay phase of drill cuttings, structuring and improving fertile soil SPSG properties.

The amount of added gypsum or phosphogypsum is calculated based on the actual salinity of drill cuttings, and ranges from 1.5 to 3%. The maximum dosage of phosphogypsum is 45-50 kg per 1 m ^{3 of} sludge, and pure gypsum requires 30% less. Given the bulk density of gypsum (phosphogypsum) - 1300-1500 kg / m ³ , the upper limit of its dosages is 3.8% of the volume of drill cuttings. Given the proportion of sludge in the volume of the final mixture, the following doses of gypsum (phosphogypsum) are recommended: 2-3% of the volume of the mixture for SPSH I and 1.5-2% for SPSH II. At such dosages, the basis of the reclamation additive is guaranteed to undergo coagulation processes and improve the properties of LNG. For more detailed calculations, it is necessary to take into account the density and moisture of the sludge, the degree of its saturation with sodium salts.

As improving and neutralizing additives, the following types of substances in small doses can be introduced into the reclamation mixture:

- sorbents (for example, ODM-2F based on opal cristobalite aluminosilicate, silica alumina based on fly ash, coal MIU-S), binding pollutants, oil products and eliminating the migration of ecotoxicants;

- drugs that accelerate the destruction (destruction of the structure) of oil products and other substances harmful to the environment: for the treatment of LNGs used for the restoration of disturbed and oil-contaminated lands, for example, microorganism strains operating under aerobic conditions (Neftedestruktor, Centrin biological products);

- fertilizers (mineral, organic, humic), neutralizing pH, improving the fertility of the material during biological reclamation: complex preparations - humic-mineral concentrate (GMC), peat-humic fertilizer "Flora-S"; organic fertilizer additives - the surface layer of organogenic soils, sawdust, sapropel, shrub layer, etc .; local organic soil, which contributes active native microflora and is a catalyst for biological processes in artificial soil.

During the experimental work, the effectiveness of the use of active neutralizing additives / microadditives was established. With the exception of sorbents and gypsum, all additives are introduced into the mixture only of the second type (SPSH II), i.e. in the upper reclamation layer.

Dosages of active microadditives are pre-assigned, and then experimentally specified in the following limits:

- the consumption of the main types of sorbents, including aluminosilicate sorbent, is calculated at the rate of 0.2-0.5 kg per 1 kg of contained (residual) oil products in the drill cuttings; taking into account the actual composition of the cuttings and the content of oil products of the order of 0.01-1%, the maximum need for sorbents is approximately 7-8 kg per 1 m ^{3 of} drill cuttings;

- the consumption of fertilizers that initiate the process of reclamation of peat and its humus, providing nutrition to plants and microorganisms, is prescribed in an amount providing a nitrogen content of at least 6 mg / 100 g of the soil mixture, phosphorus at least 12 mg / 100 g, potassium - 8 mg / 100 g;

- the recommended amount of humic preparations or natural humus-containing organic fertilizers is up to 1% of the volume of the mixture.

It should be noted that when phosphogypsum is used, the additional introduction of phosphorus fertilizers in LNG is not required, and if the drill cuttings contain KCl or other potassium salts, it is not necessary to introduce potash fertilizers.

The recommended ratio of lowland and highland peat in SPSH (option 1) is 1: 2. An increase in the proportion of fibrous (top) peat in the composition of the lower layer of SPSH provides for the sorption of mobile components of drill cuttings and a decrease in their effect on plant biocenosis.

The recommended ratio of lowland and high peat in the upper layer of SPSH (option 2) is from 1: 1 to 2: 1. The use of fine-grained decomposed and humus (grassroots) peat in larger quantities provides an increase in fertile properties, along with the sorption of components of drill cuttings. Thus, the main task of the thinner upper layer of SPSH is solved - providing conditions for plant growth and the life of aerobic microflora, which contributes to the destruction and neutralization of oil products and other toxicants, the availability of nutrients.

A more efficient use of materials and natural resources during reclamation is achieved by:

a) reduce the dosage of scarce sand and peat;

b) the use of sandy loam soil instead of building sand, as well as (when using the soil horizon removed during construction) as a source of humus and organic matter in LNG.

In the course of selecting the optimal composition of the mixtures, the Salym group of deposits with the following properties was used.

BS is a fluid-plastic (from semi-liquid to viscous consistency) paste-like mass, according to the BS certificate contains:

- cuttings - 60-70%;

- spent drilling fluid - 40-30%.

The solid phase of BS consists of drill cuttings of varying degrees of dispersion (from colloidal to 5-10 mm) and clay powders (bentonite, montmorillonite) introduced into the washing liquid, as well as insoluble and poorly soluble additives (calcium carbonate, barite, and others).

The lithological characteristics of the geological section of the wells indicate the presence of particles of sand, clay, siltstones, sandstones, mudstones, limestones, marls, glauconites and other rocks in the sludge.

The density of the particles of rocks in the range of 2.40-2.90 g / cm ³ , the porosity of 20-30%.

BS liquid phase is formed due to sorption of a certain amount of drilling fluid, as well as wastewater during equipment flushing.

The main properties of the BS of Salym deposits are given in the table.

The name of indicators Integral Sample Average The range of values for private samples, min-max Density, g / cm ³ 1.70 1.60-1.80 The density of the dry residue, g / cm ³ 1,132 1.11-1.40 Humidity% 50.28 40 60 The density of soil particles, g / cm ³ 2.75 2.40-2.90 Hydrogen indicator, units pH 9.20 7.40-9.95 Shear strength by shear resistance, kg / cm ² 0,03 0-0.05

Granulometric composition of the solid phase BS:

- content of particles with a diameter of less than 0.071 mm 60-65% - sand content 35-40% - clay phase content 20-50% The average content of oil and oil products 0.01-0.60% Medium salinity 1.0-2.4% - the density should have values within 1.30-1.80 g / cm ³ - humidity should be within 30-70%

With a lower moisture content, the BS passes into a “plastic-like” state and mixes poorly; with a higher water content, the finished SSSG has a fluid consistency and is unsuitable for compaction.

As evidence of the feasibility of implementing the claimed group of inventions with the receipt of the above single technical result, examples of specific compositions of SPSH and a description of the implementation of the claimed method are given.

Example 1

The composition of SPSH I for the lower reclamation layer, vol.%:

- drill cuttings - 65

- sand - 16

- peat - 15.5

- phosphogypsum - 3

- sorbent (based on fly ash) aluminosilicate according to TU 2164-001-47666880 - 0.5.

Example 2

Composition SPShG II for the upper reclamation layer, vol.%:

- drill cuttings - 40

- sand - 27

- peat - 30

- active neutralizing and reclamating additives, including:

- gypsum - 2

- sorbent (based on fly ash) aluminosilicate according to TU 2164-001-47666880 - 0.3

- diammonium phosphate (mineral fertilizer) - 0.05

- humus - 0.65.

Processing of drill cuttings in SPSH includes the following technological operations:

- after preliminary preparation of the OB and bringing them to the required parameters, the BS is mixed to average the composition over the entire volume of the storage or in separate sections;

- development of sludge and loading;

- transportation to the place of processing;

- development, loading and transportation of prepared peat and sand or finished peat-sand mixture;

- unloading the components of the mixture on the working platform with the formation of 1). shafts or 2). layers (with mixing cutters).

It is possible to pre-treat BS for its neutralization (if necessary) with the introduction of chemicals and active additives. In this case, dosing and distribution of drugs, mixing and aging in a barn or stack for 1-2 months. It is advisable to treat the main ameliorant (gypsum, phosphogypsum) after introducing sand into the sludge until the mixture is finally mixed with peat.

In the first case, unloading is performed in a “clamp” with the formation of three closed rows (stacks) of components.

In the second case, the soil is preliminarily imported, the peat sand mixture is prepared and spread out with a layer of 15-20 cm using a bulldozer on a gripper 100 m long with a strip width of 2.0-2.5 m. The BS is leveled with a bulldozer and, together with the peat sand mixture, is rolled with partial mixing .

Then the final mixing of the mixture is carried out, after which sampling is performed for testing and confirming the suitability of the material for use.

If necessary, ameliorants and microadditives are added to bring the hazard class to the required (no higher than IV), giving the necessary properties (for a mixture of type II). After that, the prepared mixture is collected from the grips into stacks-shoulders, aging and storage.

SPSH is a homogeneous, soil-like mixture of loose consistency. Humidity of freshly prepared material is in the range of 40-70%. SPSHG is an explosion and fireproof material, does not emit volatile toxic substances, does not dust.

The above single technical result for the object “method” is achieved due to the fact that the method of reclamation of quarries and disturbed lands includes the preparation of two soil sludge-soil mixtures (SPSH), their exposure to undergo physico-chemical reactions of coagulation and sorption and neutralization of toxicants, and layering such so that on top of the lower remediation layer SPShG I (with the content of components, vol.%: drill cuttings - 50-65, sand or sandy loam soil - 16-25, peat - 15-23, the rest - active neutralizing and reclamation containing additives, including gypsum or phosphogypsum in an amount of 2-3% of the mixture volume) lay the upper reclamation layer of SPSH II (with the content of components, vol.%: drill cuttings - 35-50, sand or sandy loam soil - 20-30, peat - 27-32.5, the rest is active neutralizing and reclamating additives, including gypsum or phosphogypsum in an amount of 1.5-2% of the mixture volume).

In the claimed method, drill cuttings are contained not only in the lower, but also in the upper reclamation layer.

For the lower reclamation layer of any thickness and for backfilling of quarries and other mine workings, type I SPG is used - slightly peat with a peat content of 15-23% of the volume. At the same time, the lower layers with a maximum content (50-65% of the volume) of clay BS serve as the parent rock and contain sorbents for binding unfavorable components of the sludge and native microflora for the destruction of hydrocarbons.

As the upper soil remediation layer, the medium-peat SPSH of type II with a peat content of 27-32.5% of the volume is used.

The addition of BS to the upper reclamation layer ensures the destruction and neutralization of oil products under aerobic conditions, under the influence of microorganisms (at the biological stage, legume crops are used in the upper layer, in the root system of which nodule nitrogen-fixing bacteria are activated, which enhance plant growth and decomposition of hydrocarbons). In addition, the addition of BS in the upper reclamation layer gives an advantage over the “clean” peat sand mixture (the upper layer in the prototype), because contributes to the preservation of moisture, prevents wind erosion, which creates better conditions for seed germination and survival of herbaceous plants at the biological stage of reclamation. Also the introduction of BSh having a pH of 7.5-9 units. (slightly alkaline medium) neutralizes peat in the upper layer, which has a pH of 4-5 units in Western Siberia, which helps to increase the fertility of the mixture.

The claimed method provides for the use of HSSG with improved structuring and improved fertile properties due to the use of gypsum or phosphogypsum as the main reclamation additive in their composition.

SPSHG I is used to eliminate (backfill) quarries, slurry pits, slopes of embankments of roads and earthworks, when laying with a layer of 0.5-1.0 m. This type of mixture is prepared by mixing the components (BS, sand, peat, ameliorant base, sorbent (microadditive)) in one go.

SPSHG II is used for surface reclamation of disturbed and contaminated lands, when laying in the upper layer with a thickness of 0.2-0.5 m. At the first stage, mixing with sand and mixing BS for the purpose of averaging the composition. Processing the main reclamant is advisable to carry out after introducing sand into the sludge, before mixing with peat. At the next stage, after laying the intermediate mixture, fertilizers, sorbents, biological products and other mini-additives are added according to the area of the treated area.

In the process of production and storage of the mixture, with stirring and holding in air for 1-30 days, the moisture levels in the stack of the mixture, the material acquires a loose or viscous-plastic consistency. Immediately before installation, the moisture content of the mixture is brought to values close to optimal during compaction (from 20 +/- 5% to 40 +/- 10%).

The material delivered to the place of use is laid in structural layers 0.3-0.5 m thick with layer-by-layer compaction during quarry reclamation or a 0.2-0.3 m layer for reclamation of disturbed lands. After laying and distribution in the structural layer, the material is compacted to achieve a compaction coefficient of at least 0.9 at a depth of 1.0 m from the ground and at least 0.8 at a laying depth of more than 1.0 m from the ground.

As a result of the implementation of the claimed method, a new mini-ecosystem is formed, which is capable of self-healing, binding, neutralizing and decomposing toxic BS compounds under aerobic conditions, as well as adapting to an external (macro) ecosystem.

Claims (10)

1. Sludge-soil soil mixture for reclamation of quarries and disturbed lands, containing peat sand mixture, drill cuttings, active neutralizing and reclamation additives, characterized in that gypsum or phosphogypsum in the amount of 2-3% of the mixture volume is used as the main reclamation additive, wherein the content of components in the mixture is, vol.%:
drill cuttings 50-65 sand or sandy loam 16-25 peat 15-23 active neutralizing and reclamating additives rest 2. The mixture according to claim 1, characterized in that the ratio of lowland and high peat in the mixture is 1: 2. 3. A mixture according to any one of claims 1 and 2, characterized in that it further comprises an aluminosilicate sorbent at the rate of 0.5 kg per 1 kg of oil products contained in the drill cuttings. 4. The soil sludge-soil mixture for reclamation of quarries and disturbed lands, containing peat sand mixture, drill cuttings, active neutralizing and reclamation additives, characterized in that gypsum or phosphogypsum in the amount of 1.5-2% of the volume is used as the main reclamation additive mixture, while the content of the components is, vol.%:
drill cuttings 35-50 sand or sandy loam 20-30 peat 27-32.5 active neutralizing and reclamating additives rest 5. The mixture according to claim 4, characterized in that the ratio of lowland and high peat is from 1: 1 to 2: 1. 6. A mixture according to any one of paragraphs.4 and 5, characterized in that it further comprises an aluminosilicate sorbent in an amount of 0.5 kg per 1 kg of oil products contained in the drill cuttings. 7. A mixture according to any one of paragraphs.4 and 5, characterized in that as active neutralizing and reclamating additives use humic preparations or natural humus-containing organic fertilizers in an amount up to 1% of the volume of the mixture. 8. The mixture according to claim 6, characterized in that as active neutralizing and reclamating additives use humic preparations or natural humus-containing organic fertilizers in an amount up to 1% of the volume of the mixture. 9. The soil sludge-soil mixture for the reclamation of quarries and disturbed lands, including the preparation of two mixtures, characterized in that the mixture used as the lower reclamation layer contains, vol.%:
drill cuttings 50-65 sand or sandy loam 16-25 peat 15-23 active neutralizing and reclamating additives, including gypsum or phosphogypsum in the amount of 2-3% of its volume rest,
and used as the upper reclamation layer, the mixture contains, vol.%:
drill cuttings 35-50 sand or sandy loam 20-30 peat 27-32.5 active neutralizing and reclamating additives, including gypsum or phosphogypsum in the amount of 1.5-2% of its volume rest 10. The method of reclamation of quarries and disturbed lands, including the preparation of two soil sludge-soil mixtures, their exposure and layering, characterized in that on top of the lower reclamation layer of the mixture with the content of components, vol.%:
drill cuttings 50-65 sand or sandy loam 16-25 peat 15-23 active neutralizing and reclamating additives, including gypsum or phosphogypsum in the amount of 2-3% of its volume rest
stack the upper reclamation layer of the mixture with the content of components, vol.%:
drill cuttings 35-50 sand or sandy loam 20-30 peat 27-32.5 active neutralizing and reclamating additives, including gypsum or phosphogypsum in the amount of 1.5-2% of its volume rest